[Programmed Death-1 Inhibitors-induced Bullous Pemphigoid in 21 Cases]

Objective To investigate the clinical features and treatments of programmed death-1(PD-1)inhibitors-induced bullous pemphigoid(BP).Methods The clinicopathological and immunohistological data of patients with PD-1 inhibitors-induced BP from Peking Union Medical Collage Hospital and reported in the literature were retrospectively analyzed.Results Totally 21 cases(15 males and 6 females)were enrolled.The average age was(70.9±9.7)years(56-86 years).The most common primary malignancies were melanoma(38.10%)and lung cancer(33.33%).The average duration from onset of PD-1 inhibitors treatment to diagnosis of BP was(49.1±23.7)weeks.Typical dermatopathological features were sub-epidermal blisters(76.19%)with infiltration of eosinophils(88.24%).Direct immunofluorescence features were linear deposition of complement C₃(95%)and IgG(75%)in the basement membrane zone.Anti-BP180-NC16A antibodies were positive in most cases(84.21%).Patients were mainly treated with systemic corticosteroids,whereas biologics such as rituximab and omazumab were also effective.Conclusions The risk of PD-1 inhibitors-induced BP should be recognized by dermatologists and oncologists.Early diagnosis and timely treatment of BP induced by PD-1 inhibitors are important to improve the prognosis.